1. Field of the Invention
The present invention relates to a device for transferring plural substrates such as a liquid crystal display (LCD) substrates and the like.
2. Description of the Related Art
LCD substrates, semiconductor wafers and others are etched, ashed, CVD-processed, sputtered and washed in the course of manufacturing LCDs or semiconductor devices. It is needed in this case that the speed at which the LCD substrates, for example, are processed is kept certain and high. A one-by-one system is thus employed instead of a batch system.
Generally, plural process chambers enclose a primary chamber (or load lock chamber) in system with the one-by-one type device. Substrate transferring means is arranged in the load lock chamber to transfer substrates one by one out of one of the process chambers into the load lock chamber or out of the load lock chamber into one of the process chambers.
Japanese Patent Disclosure Hei 4-87785 discloses a substrate process system provided with a load lock chamber in which two transferring means are arranged. This system enables the throughput to be enhanced but the two transferring means are arranged one upon the other in this case. Therefore, particles caused in the upper drive mechanism adhere to the substrate located below and contaminate it. In addition, the space which is occupied by the two transferring means is large. This makes the whole of the substrate transferring device large in size. This is contrary to today's need that the device for transferring LCD substrates must be made smaller in size.